LED module including flexible printed circuit board with adhesive layers and LED lighting fixture

Abstract

An LED module according to the present invention is an LED module including a plurality of light-emitting diodes, wherein the plural light-emitting diodes are disposed only on a lateral surface of a right cone, a right pyramid, a truncated right cone, or a truncated right pyramid; the lateral surface has an inclination angle of 55° or more and 82° or less with respect to a bottom surface; the plural light-emitting diodes have light-emitting surfaces substantially parallel to the lateral surface; and angles formed between projection lines of lines normal to light-emitting surfaces of adjacent light-emitting diodes or adjacent ones of grouped light-emitting diodes, the projection lines being drawn on the bottom surface, are all equal to each other and are 72° or less.

The invention claimed is: 
     
       1. An LED module comprising a plurality of light-emitting diodes,
 wherein the plural light-emitting diodes are disposed only on a lateral surface of a right cone, a right pyramid, a truncated right cone, or a truncated right pyramid, 
 the lateral surface has an inclination angle of 55° or more and 82° or less with respect to a bottom surface, 
 the plural light-emitting diodes have light-emitting surfaces substantially parallel to the lateral surface, and angles formed between projection lines of lines normal to light-emitting surfaces of adjacent light-emitting diodes or adjacent ones of grouped light-emitting diodes, the projection lines being drawn on the bottom surface, are all equal to each other and are 72° or less, 
 further comprising a metal base material having, in a central portion, a protrusion having a shape of the right cone, the right pyramid, the truncated right cone, or the truncated right pyramid, 
 wherein the plural light-emitting diodes are mounted on a flexible printed circuit board, and 
 the flexible printed circuit board is at least disposed so as to conform to the protrusion of the metal base material; 
 wherein the flexible printed circuit board includes a base film, a conductive pattern formed on a front surface side of the base film and including at least one land part and a wiring part connected to the land part, and a coverlay formed on a front surface of the conductive pattern and having an opening formed at a position corresponding to the at least one land part, 
 a back surface of the flexible printed circuit board has a recess extending to a back surface of the conductive pattern, the recess corresponding to at least a portion of a projection region of the at least one land part on which each light-emitting diode is mounted, 
 the flexible printed circuit board further includes thermally conductive adhesive layers filling the recess, and 
 the thermally conductive adhesive layers are a first thermally conductive adhesive layer formed on the back surface of the conductive pattern and used to fill the front surface portion of the recess, and a second thermally conductive adhesive layer formed on the back surface of the first thermally conductive adhesive layer and used to fill the back surface portion of the recess, 
 wherein the second thermally conductive adhesive layer has a lower thermal conductivity than the first thermally conductive adhesive layer. 
 
     
     
       2. The LED module according to  claim 1 , wherein the lateral surface has an inclination angle of 60° or more and 80° or less with respect to the bottom surface. 
     
     
       3. The LED module according to  claim 1 , wherein the lateral surface on which the plural light-emitting diodes are disposed includes lateral surfaces of the right pyramid or the truncated right pyramid,
 at least one light-emitting diode is disposed on each lateral surface, and 
 the right pyramid or the truncated right pyramid has a bottom surface that has a polygonal shape having 5 or more vertices and interior angles all being equal to each other. 
 
     
     
       4. The LED module according to  claim 3 , wherein the bottom surface of the right pyramid or the truncated right pyramid has an odd number of vertices. 
     
     
       5. The LED module according to  claim 1 , wherein the lateral surface on which the plural light-emitting diodes are disposed is a lateral surface of the right cone or the truncated right cone, and
 the light-emitting diodes or the grouped light-emitting diodes are disposed at equiangular intervals. 
 
     
     
       6. The LED module according to  claim 1 , wherein the protrusion of the metal base material is formed by die casting, cold forging, cutting, or press molding. 
     
     
       7. The LED module according to  claim 1 , further comprising a heat sink on a back surface side of the metal base material. 
     
     
       8. The LED module according to  claim 1 , wherein, in plan view substantially perpendicular to a surface of the flexible printed circuit board, the base film remains in a region including at least a portion of a peripheral edge of the at least one land part. 
     
     
       9. The LED module according to  claim 1 , wherein the recess is formed in a region at least covering a projection region of the opening of the coverlay. 
     
     
       10. The LED module according to  claim 9 , wherein the recess is formed in a region at least covering a projection region of the light-emitting diode, and
 the coverlay is present between the plural land parts in plan view substantially perpendicular to a surface of the flexible printed circuit board. 
 
     
     
       11. The LED module according to  claim 9 , wherein the flexible printed circuit board has a through hole for each projection region of the at least one land part, and the thermally conductive adhesive fills the through hole and a portion above the through hole and is in contact with a back surface of the light-emitting diode. 
     
     
       12. The LED module according to  claim 1 , wherein, for the right cone, the right pyramid, the truncated right cone, or the truncated right pyramid, in a −90° to 90° radial range with respect to a reference direction extending, from an origin as a center of the bottom surface, along a central axis toward an apex, a ratio of a maximum luminous intensity to a minimum luminous intensity is 2.5 or less. 
     
     
       13. An LED lighting fixture comprising the LED module according to  claim 1 . 
     
     
       14. The LED lighting fixture according to  claim 13 , being used as a light bulb.